Applicant claims, under 35 U.S.C. xc2xa7 119, the benefit of priority of the filing date of Mar. 15, 2001 of a German patent application, copy attached, Serial Number 101 12 895.9, filed on the aforementioned date, the entire contents of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a device for transmitting electrical currents, including a slip ring unit and a printed circuit board, as well as to its employment in connection with remote-controlled objects.
2. Discussion of Related Art
Slip rings are employed in many technical fields for transmitting electrical signals or electrical power from a stationary electrical unit to a rotating electrical unit. For example, slip rings are employed for the operation of remote-controlled cameras. In this application, electrical signals must be transmitted from the pivotable camera to an electronic evaluating device, and further than that also the electrical power and signals for operating of drive mechanisms, for example for zoom regulation or an electrical drive mechanism for pivoting. In the same way, electrical slip rings are used in connection with other electrical devices, for example rotatable searchlights, laser installations or robotic components.
A slip ring structure is shown in U.S. Pat. No. 3,042,998, the entire contents of which is incorporated herein by reference. In U.S. Pat. No. 3,042,998 the wires of the slip ring rotor are conducted in grooves extending in the axial direction and whose spacing in the circumferential direction has an even graduation. Because of this guidance, the wires project out of the slip ring along the rotor circumference in an orderly manner and with even spacing. No reference is made in this document to the use of a printed circuit board.
U.S. Pat. No. 5,213,374 discloses a slip ring arrangement in which a printed circuit board has been placed inside the housing of the actual slip ring unit. This printed circuit board is essentially used for signal amplification inside the slip ring unit. The internal printed circuit board of this patent disclosure cannot transmit a torque, because an appropriate housing has been provided there for this function. Moreover, no ordered guidance in the sense of a functionally-related local assignment of the connecting wires to the printed circuit board is provided in U.S. Pat. No. 5,213,374, the entire contents of which is incorporated herein by reference.
A wireless slip ring is disclosed in U.S. Pat. No. 4,870,311, the entire contents of which is incorporated herein by reference. In U.S. Pat. No. 4,870,311 strip conductors on printed circuit boards are used in place of the wires in the slip ring unit. The printed circuit boards, all of which are located inside the slip ring unit in accordance with this patent, are connected as flexible cables, which assure the connection with external devices. A flange is provided, which is fastened on the rotating body and is used for an appropriate introduction of a torque.
The above-described known devices have the disadvantage that the torque required for the relative movement between the rotor and the stator is supplied via separate mechanical devices which must be provided in addition to the already present printed circuit boards. In particular, in connection with slip ring units which are produced in large numbers, it is necessary to achieve a material-saving construction, which moreover requires the fewest number of components.
Further details of the present invention ensue from the following description of an exemplary embodiment by the attached drawings.
An object of the present invention is therefore based on making possible a slip ring unit with a printed circuit board which is distinguished by a simple and cost-effective construction.
This object is attained by a device for transferring electric currents that includes a slip ring unit that has a rotor with connecting wires and a stator and a printed circuit board fastened to the rotor, wherein the printed circuit board includes connectors in electrical contact with the connecting wires, wherein a torque required for rotary movement between the rotor and the stator is introduced via the printed circuit board.
The above-mentioned object is also attained by a device for transferring electric currents that includes a slip ring unit that has a stator with connecting wires and a rotor and a printed circuit board fastened to the stator and having connectors that are in electrical contact with the connecting wires of the stator and wherein the printed circuit board is used as a torque support.
Other aspects of the device in accordance with the present invention are intended to be used for operating remote-controlled objects.
A slip ring unit is understood to be a device including a rotor and a stator and has connecting wires, which are conducted inside the slip ring essentially in the axial direction and are respectively in electrical contact with sliding contacts at the stator and rotor. The connecting wires can be embodied either as a solid cable, or as stranded conductors including several twisted individual wires. The connecting wires are customarily surrounded by an insulating layer, which is often removed in the area of the ends of the connecting wires. The above mentioned sliding contacts (for example rings and matching spring-loaded wire elements) should be mentioned as further components of the slip ring unit, which are in sliding contact when the slip ring is in operation and transmit the electrical current. In particular, those slip ring units are addressed in what follows, in which the rotor and stator have an essentially cylindrical, or hollow-cylindrical, form.
In what follows, electrical current is understood to mean electrical signals, as well as electrical current for transmitting power, or energy.
The advantage achieved by the present invention resides in that the number of components for a slip ring unit with a printed circuit board is reduced by the novel device. The entire construction is simplified in this way, and a material-saving design of this device is made possible, so that a cost-effective technical solution is also achieved in the end. On the other hand, the outlay for assembly, or for putting together the device in accordance with the present invention, becomes comparatively small. Further than that, an extremely small structural depth of the slip ring unit with the associated mechanical connector is achieved.
The present invention is based on the concept that the printed circuit board not only transmits electrical currents, but also the torque required to be produced for the relative movement between the rotor and the stator. In this case, it is possible either to introduce the torque into the rotor by the printed circuit board, or the printed circuit board is used as a torque support at the stator in order to produce a corresponding reaction force.
Moreover, the connecting wires which are conducted out of the slip ring unit are advantageously put in order in such a way that their function is correlated with the respective connecting wire position, so that a printed circuit board with an appropriate connecting pattern can be connected simply and assuredly with the slip ring unit. Because of this, it is possible to perform the connecting process between the connecting wires and the printed circuit board completely or partially automatically.
However, the present invention also includes arrangements in which the printed circuit board is fastened on the stator, so that the rotary movement then need not necessarily be introduced into the rotor by a further printed circuit board. In this case, it is decisive for the present invention that the printed circuit board at the stator transfers the reaction force from this rotary movement quasi in the form of a torque support to a stationary device. The idea of the present invention is therefore independent of whether the printed circuit board is fastened on the rotor or the stator.
A possible exemplary embodiment of the present invention will be explained in greater detail by the drawings.